Warp knit elastic fabrics are often used as belting for undergarments where the belting of fabric is sewn along a lower edge to the undergarment and where the upper edge is free to contact the skin of the wearer. Many forms of such fabrics in the past have been subjected to unraveling particularly when one end of a belt or strip of fabric joins with another end of the fabric by means of a butt-type joint. If through a production error, a portion of the upper edge of the fabric extends above the butt joint, this portion through use may have a tendency to unravel.
A locking yarn has been used in the past to overcome any tendency of the upper edge to unravel whereby the locking yarn was knitted into each course of two wales adjacent a lateral top edge of the fabric to form an open loop in alternate wales. A further prior art construction of a warp knit elastic fabric utilizing a ravel resistant locking yarn is disclosed in my U.S. Pat. No. 4,003,224 dated Jan. 18, 1977 where a locking yarn is knitted into an end or locking wale to form open loops in alternate courses and where the yarn is laid in a weft direction over a number of wales in the remaining courses. However, both of these uses of a locking yarn has been restricted to a warp knit fabric having a square edge construction in which the weft or filler yarns overlie each other and extend over and beyond the lateral end wale of the fabric. Such uses of a locking yarn are not applicable to warp knit fabrics having a crisscross edge construction wherein the weft or filler yarns extend in opposite directions to alternate with one another in the direction of fabric thickness.
It is therefore an object of my invention to provide for an elastic warp knit construction having a high degree of resistance to unraveling where the fabric may comprise either a square edge of crisscross edge construction.
A further problem existing with prior art elastic warp knit fabrics used for belting for undergarments and the like is that the edge of the fabric contacting the skin of the wearer tends to pinch the skin when the fabric contracts after being stretched thus giving a feeling of a rough edge. It is a further object of my invention to provide for a warp knit elastic fabric construction having an edge which will not pinch the skin of a wearer and which will have a soft edge and where the construction will still provide a fabric having dimensional stability when in a relaxed or untensioned state.